High-temperature oxidation process of intermetallic compound Ti-42 at% Al

The oxidation process of two-phase (Ti₃Al and TiAl) intermetallic compound, Ti-42 at% Al, in air at 1073 and 1273 K has been investigated. The oxidation at 1273 K is much faster than that at 1073 K; however, the oxidation kinetics are similar. During heating up, TiO₂ scale forms initially on the compound surface at about 973 K, and then Al₂O₃ scale forms at about 1273 K. For the isothermal heating, TiO₂ scale slowly grows up at 1073 K, while at 1273 K both TiO₂ and Al₂O₃ scales grow up drastically. The outer oxide scale consists of TiO₂ and the inner one consists of a mixture of TiO₂ and Al₂O₃. The volume of Al₂O₃, which forms after TiO₂ formation at the initial stage of oxidation, is larger at an area adjacent to the oxide-compound interface.